Guiding System of the Spectro-Stratoscope

The characteristics of the guiding system of the Spectro-Stratoscope (a balloon-borne solar telescope) for spectroscopic studies of the sun are described. The telescope system is almost completely decoupled from the balloon suspension. Hydrostatic bearings and a spherical torque motor are described in detail. The fine-stage guiding system locking on the solar granulation is described and the principle of automatic focusing explained.